The invention is directed to an apparatus for cleaning the clips of a web transporting machine. In particular, the invention is directed to an apparatus for cleaning the clips of web transporting machines of the variety where there can be significant chemical and debris buildup on the clips, such as a tenter frame.
A variety of apparatus exist for transporting and processing webs of material, such as textile fabric webs and the like. Such machines typically include devices for holding the sides of the web, and a means for transporting the web along a predetermined pathway, which is generally through one or more processing stations. One example of such a web processing apparatus is a tenter frame. As will be appreciated by those of ordinary skill in the art, tenter frames are used to dry textile materials, and can be used to control the fabric width by controlling the amount the fabric can shrink when heated during the drying process. Typically, tenter frames include a pair of endless chains on horizontal tracks, which hold the fabric at its edges by pins or clips on the two chains, to thereby hold the fabric at the desired width during drying. Similarly, other web processing machines use clips to retain the edges of the web during processing, to maintain it in a desired position for processing and/or control its width.
The clips typically used on these kinds of machines generally have a lower, flat web supporting portion that is adapted to support the web being processed beneath the web edges (or selvages, as they are known in the textile industry.) The clips also typically have a hinged flap that pivots downwardly toward the web supporting portion, to capture the web edge and retain it tightly in position. The hinged flap is desirably designed to pivot in the direction such that the more a fabric is pulled away from the clip, the more tightly the flap is pulled toward the web supporting portion. In this way, the hinged flap is enabled to tightly secure the web edges, while being relatively easy to open when so desired, by pivoting it in the opposite direction.
One difficulty experienced with such apparatus is that the foreign matter can tend to build up on the clips, and in particular, on the surface of the web supporting portion. Not only can this interfere with the proper closing of the flap and securement of the web (leading to miss-clips and inadequate dimensional setting of the web), but the foreign matter can soil the web being processed, thereby causing off-quality or defects. The problem of clip contamination build-up can be particularly aggregious in the processing of textile materials, where a variety of chemistries and finishes are often provided on the fabrics. Furthermore, since tenter frames are typically operated at elevated temperatures (e.g. from about 150xc2x0 F. and upwards), it often results that the chemicals and finishes are xe2x80x9cbaked onxe2x80x9d, which can make them extremely difficult to remove. As a result, it is generally required that clip contaminants in the textile environment be removed by the manual scraping of the clips with a putty knife. As will be readily appreciated by those of ordinary skill in the art, this has disadvantages in terms of safety, speed, manufacturing efficiencies, and the like.
Attempts have been made to automate clip cleaning. For example, U.S. Pat. No. 4,176,429 to Rottensteiner describes a brush system for cleaning the clips on a tenter frame. The brush cleaning device is designed to move between an operative, clip contacting position, and an inoperative position. While such brushes may be sufficient for certain end uses where the clip contamination is in xe2x80x9cfree flakexe2x80x9d form, it would be insufficient to remove chemistry and finishes in many applications, and in fact, would tend to make it more difficult to remove, in that it has been brushed and compacted onto the clip surface.
Other attempts to free obstructions in tenter clips are described in U.S. Pat. No. 3,789,975 to Ida et al, and U.S. Pat. No. 5,771,547 to Hommes et al. Those patents describe the use of streams of pressurized air to eject foreign matter from the tenter clips. Like the brushing technique described in the Rottensteiner patent, this method would be insufficient for removing baked-on material of the variety described above.
Other methods have generally accepted that clip contamination cannot be sufficiently avoided, and have focused on the identification of contaminant build-up. For example, U.S. Pat. No. 5,159,733 to Fleming, Jr. et al describes a tenter machine having a mechanical arm or a light beam for detecting foreign matter on the clips, in order that the machine operation can be ceased.
With the foregoing in mind, it is therefore an object of the invention to provide an apparatus for the automated cleaning of clips on a web processing apparatus, which will enable the removal of chemicals and finishes such as those encountered in a textile processing environment.
It is also an object of the invention to provide a means for cleaning the clips of a web processing apparatus that can be readily applied to existing equipment, without requiring redesign or modification of the equipment.
It is another advantage of the invention to provide an apparatus that can effectively clean the clips of a web processing machine while the machine is in operation and the clips are moving at high rates of speed.
To this end, the present invention is directed to an apparatus for cleaning the clips of a web processing apparatus which can be easily applied to any of a variety of web processing devices, and which can remove securely attached debris and contaminants from the web supporting surface of the clips. The apparatus includes a scraper for scraping the web supporting surface of the clips on the web transporting machine, and also desirably includes a clip opener, for facilitating opening of the clips to enable the scraper to easily access the web supporting surface of the clip. The scraper is desirably supported in a manner that enables it to move upwards and downwards relative to the clips in order to accommodate variations in clip positioning.
The clip cleaner is also desirably designed so that it can clean the clips while the web processing device is in operation, and operating at the high speeds typically used during a commercial processing operation.